scudderfish
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 posted on 9/9/13 at 01:53 PM |
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Earthing techniques
I'm chasing down some (a lot) of ECU resets so I decided to redo my earths to the engine block. If I have half a dozen earth wires for
ECU/sensors, what is the best way to attach them to the block? I'm looking to hang everything (including earth strap from block to chassis and
mounting for the 20uF suppressors) from one bolt into my passenger side head.
Regards,
Dave
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loggyboy
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| posted on 9/9/13 at 02:33 PM |
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Why not earth some of the important ones directly to the battery or chassis (such as ecu or injection etc components)
If not the simplest way is a good crimped ring terminal bolted to a clean bolt hole on the block. Add some grease to keep the rust to minimum.
There is no special trick that im aware of other than keeping all the connections on a clean surface on initial fitment.
Mistral Motorsport
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Slimy38
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| posted on 9/9/13 at 02:37 PM |
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I quite liked the way my MX5 donor dealt with earths. It had a copper strip about two inches wide and about half an inch deep. On one of the long
sides there was a round terminal that was bolted to the chassis. The other side had about half a dozen spade connectors where all the earths were
connected.
This is a similar idea;
http://www.thetoolboxshop.com/0-005-35-1-pack-of-1-630mm-six-way-male-blade-terminal-block-8406.html?gclid=COf40M3EvrkCFYZb3godKz4APw
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loggyboy
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| posted on 9/9/13 at 03:08 PM |
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I bought these for mine to do a similar job for the chassis earths:
Solid Brass Head Earth Terminal Mass Blind Pop Rivet Choose 1 or 2 Tabs / Spades
[Edited on 9-9-13 by loggyboy]
Mistral Motorsport
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atm92484
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| posted on 9/9/13 at 03:25 PM |
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This is how I do it:
1) Figure out the circular area unit for each wire ( http://www.pinsandsockets.nl/circular_area_units.htm )
2) Add these numbers together (IE two 20 gauge wires and two 18 gauge wires would have a CAU of 12+12+19+19=62)
3) Pick the correct sized ring terminal (since 62 is in the range for a 10-12 gauge ring terminal's CAU values, this would be the correct
size)
Strip the wires, twist them together, stick them in the right size terminal and crimp or solder.
[Edited on 9/9/13 by atm92484]
[Edited on 9/9/13 by atm92484]
-Andrew
Build Log
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Scuzzle
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| posted on 9/9/13 at 03:46 PM |
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This looks neat
8 way nickel plated brass earth terminal block
By the looks of it you bolt it to the body through the top and bottom holes to secure then run all your earths to it.
Edit - Noticed you can also get half sized ones for half the price as well.
If you don't have metal panels I suppose a HD earth strap under each bolt hole to the block or battery earth would work.
[Edited on 9/9/13 by Scuzzle]
[Edited on 9/9/13 by Scuzzle]
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BaileyPerformance
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| posted on 9/9/13 at 06:18 PM |
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The sensor earths (0v) should return to the Ecu 37w connector, not the engine block or chassis, the tps and vr sensors should be wired in screened
cable.
Then the Ecu ground wires should be connected to the engine block.
The battery negative should be connected with at least 25mm cable to the block, then at least one heavy ground wire from the block and/or the battery
to the chassis.
The 12v supply to the Ecu should be the same supply as the injectors, NOT directly from the ignition key but via a dedicated relay from the battery.
(Relay coil powered from the ignition key) coilpack supply directly from the ignition key.
The alternator should be well grounded to the block, the alternator + output directly to the battery.
Some old Lucus alternators are noisy, later Bosch ones are much better.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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MikeRJ
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| posted on 10/9/13 at 06:29 AM |
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quote:
Originally posted by BaileyPerformance
The sensor earths (0v) should return to the Ecu 37w connector, not the engine block or chassis, the tps and vr sensors should be wired in screened
cable.
This is absolutely the only correct way to do things. If you ground two wire sensors to the engine block then all the noise and voltage drops
introduced by the power circuits (e.g. alternator) will be directly summed into your sensor values.
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scudderfish
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| posted on 10/9/13 at 07:41 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by BaileyPerformance
The sensor earths (0v) should return to the Ecu 37w connector, not the engine block or chassis, the tps and vr sensors should be wired in screened
cable.
This is absolutely the only correct way to do things. If you ground two wire sensors to the engine block then all the noise and voltage drops
introduced by the power circuits (e.g. alternator) will be directly summed into your sensor values.
Possibly where I was going wrong as my TPS, CLT and air temp sensor were all earthed on the block at the same point as the ECU.
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